A semiconductor manufacturing process may comprise a number of separate subtasks. A subtask may comprise a set of operational steps that are all performed on a single entity. An entity is a physical object (e.g., a tool) that is used in the manufacture of the semiconductor wafers. For example, an entity may be a diffusion wetdeck, an implanter unit, a semiconductor oven, or any other similar type of manufacturing equipment. A semiconductor manufacturing process may utilize the entities to manufacture particular types of semiconductor wafers. The particular types of semiconductor wafers are referred to as inventory.
Prior art manufacturing execution systems exist that are capable of controlling a semiconductor manufacturing process. A manufacturing execution system comprises computer hardware and computer software that is capable of controlling the entities and the inventories that are used in the manufacture of semiconductor wafers. A manufacturing execution system receives information concerning the status of the different entities and concerning the status of the different inventories during the manufacture of semiconductor wafers.
The various processes of the semiconductor manufacturing process must be performed on the correct inventory using the correct entities in the correct order. If the manufacturing execution system determines that a particular inventory is not being used on a correct entity, then the manufacturing execution system will not allow the entity to operate. Similarly, if the manufacturing execution system determines that a particular inventory is not being processed on an entity in a correct order, the manufacturing execution system will not allow the entity to operate until the inventory is processed in the correct order.
There may be various restrictions that are put in place to regulate whether a particular entity (i.e., a particular tool) may be used to perform work on a particular type of inventory (i.e., a particular type of wafer lot). The manufacturing execution system keeps track of all of the restrictions imposed on the various entities and inventories of which the manufacturing execution system is aware. There may also exist various restrictions that are not known to the manufacturing execution system.
The restriction information in prior art manufacturing execution systems is not easily accessible to a user. Often a user is completely unaware of the existence of any restriction until the manufacturing execution system will not perform a requested procedure. In many instances the first time that the user knows that a particular entity will not accept a particular inventory is when the user tries to perform work on the inventory using the entity.
When the user finds out that a restriction exists, the user has to stop the semiconductor manufacturing process, search for the reason that the restriction exists, and then try to find a person who is authorized to remove the restriction. This procedure wastes valuable semiconductor processing time because the semiconductor manufacturing process is halted until the restriction information is located and the restriction is removed.
Therefore, there is a need in the art for a system and method that is capable of quickly and effectively identifying restrictions that have been placed on entities and inventories during a semiconductor manufacturing process.